Field



- NITE STATES: Planar curios.

me e ABBOTT HADFIELD, or LONDON, ALExAnnna-cmonen MACKENZIE JACK, or

- I SHEFFIELD, ANDISAAG BERNARD MILNE, OF TOTLE'Y, ENGLAND.

MANUFACTURE OF ARMOR-PIERCING PROJECTILES.

To all wlto m'z't may concern:

Be it known that we, ROBERT ABBOTT HAD- FIELD, ALEXANDER GEORGE MACKENZIE J ACE, and ISAAC BERNARD MILNE, subjects of the King of Great Britain and Ireland, residing at 22 Carlton House Terrace, London, Rocklarge diameter, say. of twelve inches and upward, that shall be better adapted than those heretofore commonly used to completely perforate thick hard faced armor plates without becoming broken up, or broken to such an extent as to interfere with their a subsequent desired action. v

Forthis purpose an armor piercing shell according to the present invention is made of suitablesteel, such as nickel chromium steel, and subsequently treated in such a manner that the head or. ogival forward portion .of the shell is of different degrees of hardness varying say from a ball hardness of from about 600 to 700- at the pointed front end portionor zone through successive rearward zones of about 500,; 400 and 300 ball hardness, the zone having a ball hardness' of about 400 terminating'rearward1y say round about the forward portion of the cavity in theshell and the zone having a ball hardness of about 300 extending. farther rearward for a short distance around the shell cavity, the remaining rearward portion of the shell having a ball hardness under 300.

In the production of such a shell, made say of nickel chromium steel, the shell after being formed to shape, as by casting it solid and. then, after suitably annealing it, by

pressing it to shape in a suitable press, is

hardenedand tempered by subjecting it to two separate treatments of which the first consists 'in heating the shell all over in a suitable furnace to a hardeningtemperature, the point of the projectile being protected from direct contact with the heating medium in a known manner to prevent overheating thereof and then dipping the shell point downward to its base end .in a coolin medmm, for example 011, where it 1s le t Specification of Letters Patent. P t tgd July 15, 1919,, Application flled'June 28, 1915. Serial No. 36,886. i v

until cold. The second or tempering treat- 'ment consists in heating. the ase portion of the shell to a suitable tem ering tem perature while its pointed emf portion is immersed point downward, to a suitable depth in water, after which it is artially cooled and then immersed or quenc ed out rigtlt in a cooling medium, for example we r.

The temperatures to which the shells are heated, the depths and durations of immersion and other details can be variously modified to suit different sizes of shells and the cha'acter of the steel of which they are ma e.

According to one example, carried out ..7%; nickel 2 to 3% and chromium 2 to 3%, for example carbon about 56%, nickel about 2.52% and chromium about 2.31%, the shell was heated all over to a hardening temperature while its point was protect ed from dire'ctcontact with the heat so that the externaljshoulder ortion of the shell had a temperature of a out 915 C. to 920? C., the inner surface or core adjacent to the shoulderportionbeing found tohave, in the example given, a temperature of about 900 to 905 0., the point a temperature of about 890 C., and the base a temperature of about 7 80 C. The shell thus heated was then hardened all over b dip in it in oil to its base end and hol ing it tiere until practically cold, the cooling being effected from the exterior alone, that'is to say without admittin interior of t e shell. The hardened shell was afterward subjected to a second or tempering treatment consisting in heating the aseportion thereof in a furnace to a temperature of about 670 to 705 0.; its interior or core having a temperature of about 605 C. while its pointed end portion of about 290 to 255 C. whereu on it was y en thus quenched outright in water. treated, the pointed portion of the shell for about the first ten inches of its length had any cooling medium to the I a ball hardness of 600 and over, theweight I of, this portion comprising about 12% of the total weight oftheprojectile, the ball. hardness. varying from' 600 at ten inches from the point to 418 at fourteen inches, 31-1 at'18 inches and 241 at the base end of the shell.

According to anotherexample carried out with .afourteen" inch shellv having a length of about fifty-two inches and made-of nickel chromium steel having the following approximate composition,. v'iz.,'carbon 139% I so that the external shoulderortion of the "shellf had a temperature-oft out-930 (1;, .the' inner surface orj jcore adjacent to the; shoulder beingffound tohave' in this example a temperature of about 900 to 905 (3., the point atemper'ature of about" 875? and the base a'temperature of about850g Theshell thus heated-was then'dipped inr oil to its base end and held in thatv position] until cold, the cooling being-effected; wholly 1 from the exterior inward. F'Ihe-Ihardened shell was afterward subjected to ya second or tempering treatment consistin in heat ing the base to a temperature of a 'ut- 700 v 0., its interior or' core having a temperature of about 630 C. while its point vwasTimmersed for about a depth of eight, inches in water kept cold. Theshell wasthen allowed to cool down in the furnace to a ase,

temperature of about 310 Cgand, av 1 core temperature of about 255 C. and 7 then quenched outright in water. In this case the first eight inches had a ball hardness of 652 and over, this portion constituting"- about 6% of the weight of the shell, the

hardness decreasing to the base where it was about 262. v a

From the foregoing examples it will be seen that the temperatures to which the various parts of the shell canbe heated and the manipulation of the shell can be variously modified without departing from the essential features of the invention.

The second or tempering treatment can rst'or hardening treatment as here circumstances.

-. shell an over ,to an lan iile in ,4; The? process 'of.- ;.;producing" an armor p'iei cing proj ectile havin'gjthe head of d-ifier- I 1 internal cooling. I I .v 6. The process of treatmgan armor piercbe applied to shells sub- 115 .Wh'at we claim is I Q 1. The" process o fheating an armor piercshell which consists in heatingthe shell over toa hardening temperature, then treat hich-consists injheatingthe while'proteeting'the m hen di P e theg shelli 'to ts p a cool f 11 g PM 6 s: ifl i on ist hi l hati g, e i shell 'all'fover to a:"*}iardening temperature whil pr c i g th point from dir t "ca .tact; withijthe heating' medi'um, and then dipping theshell p'ointdownward ,in fa? I H re lp armoi: pierc- I 35 ageing mp ra there till: practical y c0l d.-f-;

pointed frontend-from about 700110 600' ball hardness; diminishing inf-hardnesfs' to about 400 at about the ffrontf end of I the cavity, about -300 farou'nd the cavity. and, the rear- 'wardf'port'ion under"30O, which' consists in heating thepljojeotileial-loverto a hardening -temp eraturef theexternal shoulder portion about 900950.11 over','the point about 900 Gear sa -little under,- and the base about or :"un d'gr 800 0., and thendipping the shell inq'a; cooling medium and leaving it there till practically cold. 5:. The process of heating an armor piercing shell which consists in .heating the shell throughout and leaving it there until comparatively cold, the cooling being effected without special from the exterior inward ingprojectile which consists in heating the shell all over, to a. hardening" temperature,

' all overwtoai'hardening. temperature, then dipping the shell point downward to base l-in a cooling medium of the same character then dipping theshell oint downward in" a cooling medium and a1 owing it to remain I there until practically cold and subsequently subjecting the hardened shell to a tempering treatment or nsisting in heating the base or I portion ofthe shell to a suitable tempermgtemperature while the point of; the

.ggefi is kept cool, and afterward cooling the The process of treating anarmor ierre:

and owing it to remain therein until it is I gshell which oonsistsin heating the shell all over to; a hardenin temperature then dippgiig the shell to base in a cooling medium practically cold, then heating the base of the hardened shell to a suitable tempering temperature while the point of the projectile is immersed in a cooling medium, then allowing the shell to partially cool and there-' after quenching the shell outright in a cooling medium.

8. The herein described process of hardening an armor piercing projectile which consists of producing a projectile of the approximate composition:carbon about .0 to .7 nickel about 2. to 3., and chromium about 2. to 3., heating the projectile all over to a hardening temperature while protecting the point, and then dipping the projectile to its base in a cooling medium and leaving there till cold.

9. The herein described process of hardening an armor piercing projectile which consists in heating the shell to a hardening temperature, then dipping the projectile in a cooling medium and allowing it to remain there till cold, and then tempering the projectile by heating the base to a tempering temperature while protecting the Point and then cooling.

10. The process of treating an armor piercing projectile which consists in heating the shell all over to a hardening temperature while protecting the point from direct con tact with the heating medium, and then dipping the shell point downward in a cooling medium and leaving it there until cold, then ten'iperingthe projectile by heating the base to a tempering temperature, while its pointed end portion is immersed in water. then partially cooling and then quenching outright in a cooling medium.

11. The process of treating an armor piercing projectile which consists in heating the shell all over to a hardening temperature while protecting the point and then dipping the shell to its base in a cooling medium and leaving it there till cold, and then tempering the same by heating the base to a tempering temperature while protecting the point, then partially cooling and then quenching in water.

12. The process of producing an armor piercing projectile having the head of different degrees of hardness varying at the pointed front end from about 700 to (300 ball hardness, diminishing in hardness to about l00 at about the front end of the. cavity, about 300 around the cavity and the rearward port-ion under 300, which consists in heating the projectile all over to a hardening temperature, the external shoulder portion about 900 C. or over, the point about 900 C. or a little under, and the base to about or under 800 C. and then dipping the projectile in a cooling medium and leaving it there till cold. and then tempering the projectile by heating the base in a furnace to a temperature of about 670 to about 705 C. its interior having a temperature of about 605 C... while its pointed end is immersed to about eightand one half inches in water kept cold, then permitting the projectile to cool in the furnace to a base temperature of about 320 C. to about 300 C. and a core temperature of about 290 C. to about "255 (3., and then quenching the same outright in water.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

Witnesses WM. .CRoss, WM. 0. BROWN. 

